Envoy Is Turned Back After Arrival at Dulles

WASHINGTON—The State Department on Tuesday blocked the entrance into the United States of a senior Syrian diplomat who was assigned by President Bashar al-Assad's government to staff Damascus's embassy in Washington, according to U.S. officials.

The diplomat arrived Tuesday morning at Washington's Dulles International Airport, according to U.S. officials, who said he had been issued a visa by mistake. Word of his Tuesday morning arrival prompted outrage from congressional staff members and Syrian opposition groups who...